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Find video protocols related to scientific articles indexed in Pubmed.
Psychiatric Disorders Among Obese Patients Seeking Bariatric Surgery: Results of Structured Clinical Interviews.
Obes Surg
PUBLISHED: 11-01-2014
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Obesity and psychiatric disorders are burdensome health problems commonly observed in general population and clinical samples. However, non-standardized assessment and small size of the sample might hamper conclusions of the investigations. The objective of this study is to replicate previous findings on frequency of psychiatric disorders and associated factors among obese patients seeking bariatric surgery, assessed through standardized interview.
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Casp8p41 generated by HIV protease kills CD4 T cells through direct Bak activation.
J. Cell Biol.
PUBLISHED: 09-22-2014
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Previous studies have shown that human immunodeficiency virus (HIV) protease cleaves procaspase 8 to a fragment, termed Casp8p41, that lacks caspase activity but nonetheless contributes to T cell apoptosis. Herein, we show that Casp8p41 contains a domain that interacts with the BH3-binding groove of pro-apoptotic Bak to cause Bak oligomerization, Bak-mediated membrane permeabilization, and cell death. Levels of active Bak are higher in HIV-infected T cells that express Casp8p41. Conversely, targeted mutations in the Bak-interacting domain diminish Bak binding and Casp8p41-mediated cell death. Similar mutations in procaspase 8 impair the ability of HIV to kill infected T cells. These observations support a novel paradigm in which HIV converts a normal cellular constituent into a direct activator that functions like a BH3-only protein.
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Validation of the Brazilian-Portuguese version of the Modified Telephone Interview for cognitive status among stroke patients.
Geriatr Gerontol Int
PUBLISHED: 09-07-2014
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To examine the psychometric properties of the Brazilian version of the Modified Telephone Interview for Cognitive Status (TICS-M) for cognitive impairment in post-stroke patients from the Stroke Mortality and Morbidity Study.
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Low-mass molecular dynamics simulation: a simple and generic technique to enhance configurational sampling.
Biochem. Biophys. Res. Commun.
PUBLISHED: 08-30-2014
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CLN025 is one of the smallest fast-folding proteins. Until now it has not been reported that CLN025 can autonomously fold to its native conformation in a classical, all-atom, and isothermal-isobaric molecular dynamics (MD) simulation. This article reports the autonomous and repeated folding of CLN025 from a fully extended backbone conformation to its native conformation in explicit solvent in multiple 500-ns MD simulations at 277K and 1atm with the first folding event occurring as early as 66.1ns. These simulations were accomplished by using AMBER forcefield derivatives with atomic masses reduced by 10-fold on Apple Mac Pros. By contrast, no folding event was observed when the simulations were repeated using the original AMBER forcefields of FF12SB and FF14SB. The results demonstrate that low-mass MD simulation is a simple and generic technique to enhance configurational sampling. This technique may propel autonomous folding of a wide range of miniature proteins in classical, all-atom, and isothermal-isobaric MD simulations performed on commodity computers-an important step forward in quantitative biology.
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[Comparison of genetic damage in mice exposed to black carbon and ozone-oxidized black carbon].
Beijing Da Xue Xue Bao
PUBLISHED: 06-20-2014
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To make an assessment on the genotoxicity caused by black carbon (BC) and ozonized black carbon (O?-BC).
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Attitude and impact of perceived depression in the workplace.
Int J Environ Res Public Health
PUBLISHED: 03-28-2014
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Information concerning the occurrence and consequences of depression in the workplace is scarce. This study estimates how workers perceive depression, to investigate depression-related disabilities, and management of depression in the workplace. This investigation is based on a cross-sectional web-based survey of 1,000 workers recruited from online sources. The participants were Brazilian workers, aged 16-64 years, current workers and managers, or who have worked within the past year. Subjects answered a 13-item questionnaire about depression, its related consequences in the workplace, and available resources to handle depression. Common symptoms attributable to depression were crying, loss of interest, and sadness. Almost one in five participants reported having ever been labeled by a doctor/medical professional as suffering from depression. However, the majority of ever-depressed workers (73.5%) remained working. Performance-related impairments were reported by around 60% of depressed workers who continued working. Over half of them also complained about cognitive symptoms (concentration difficulties, indecisiveness, forgetfulness). One in three workers had taken off work due to depression (mean 65.7 out-of-role days), with these periods being lengthier for men than women. Managers underestimated the number of days out-of-role (29.5 days). The findings suggested that identification and management of symptoms of depression should be set as a priority in worker's health care.
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Observation of allylic rearrangement in water-rich reaction.
Chem. Commun. (Camb.)
PUBLISHED: 02-04-2014
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Allylic rearrangement or the migration of a double bond from its original position in the carbon skeleton to an adjacent site was observed when 3,4,5,6-tetrahydrophthalate was hydrolyzed in a basic solution and in the presence of Co(ii) and Mn(ii) under hydrothermal conditions.
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DSM-5 latent classes of alcohol users in a population-based sample: results from the São Paulo Megacity Mental Health Survey, Brazil.
Drug Alcohol Depend
PUBLISHED: 01-03-2014
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We aimed to identify different categorical phenotypes based upon the DSM-V criteria of alcohol use disorders (AUD) among alcohol users who had at least one drink per week in the past year (n=948).
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Drinking patterns and alcohol use disorders in são paulo, Brazil: the role of neighborhood social deprivation and socioeconomic status.
PLoS ONE
PUBLISHED: 01-01-2014
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Research conducted in high-income countries has investigated influences of socioeconomic inequalities on drinking outcomes such as alcohol use disorders (AUD), however, associations between area-level neighborhood social deprivation (NSD) and individual socioeconomic status with these outcomes have not been explored in Brazil. Thus, we investigated the role of these factors on drink-related outcomes in a Brazilian population, attending to male-female variations.
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[Autoregressive integrated moving average model in predicting road traffic injury in China].
Zhonghua Liu Xing Bing Xue Za Zhi
PUBLISHED: 11-22-2013
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This research aimed to explore the application of autoregressive integrated moving average (ARIMA) model of time series analysis in predicting road traffic injury (RTI) in China and to provide scientific evidence for the prevention and control of RTI. Database was created based on the data collected from monitoring sites in China from 1951 to 2011. The ARIMA model was made. Then it was used to predict RTI in 2012. The ARIMA model of the RTI cases was Yt = e(Y?t-1+0.456?Yt-1+et) (et stands for random error). The residual error with 16 lags was white noise and the Ljung-Box test statistic for the model was no statistical significance. The model fitted the data well. True value of RTI cases in 2011 was within 95% CI of predicted values obtained from present model. The model was used to predict value of RTI cases in 2012, and the predictor (95%CI) was 207 838 (107 579-401 536). The ARIMA model could fit the trend of RTI in China.
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Evaluation of the BH3-Only Protein Puma as a Direct Bak Activator.
J. Biol. Chem.
PUBLISHED: 11-21-2013
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Interactions among Bcl-2 family proteins play critical roles in cellular life and death decisions. Previous studies have established the BH3-only proteins Bim, tBid and Noxa as direct activators that are able to initiate the oligomerization and activation of Bak and/or Bax. Earlier studies of Puma have yielded equivocal results, with some concluding that it also acts as a direct activator and other studies suggesting that it acts solely as a sensitizer BH3-only protein. In the present study, we have examined the interaction of Puma BH3 domain with Bak by surface plasmon resonance, assessed Bak oligomerization status by cross-linking followed by immunoblotting, evaluated the ability of the Puma BH3 domain to induce Bak-mediated permeabilization of liposomes and mitochondria, and determined the effect of wildtype and mutant Puma on cell viability in a variety of cellular contexts. Results of this analysis demonstrate high affinity (KD ~ 30 nM) but transient binding of the Puma BH3 domain to purified Bak ex vivo, leading to Bak homo-oligomerization and membrane permeabilization. In a cellular context, mutations in Puma that inhibit (L141E/M144E/L148E) or enhance (M144I/A145G) Puma BH3 binding to Bak also produce corresponding alterations in Bak oligomerization, Bak-mediated membrane permeabilization and Bak-mediated killing. Collectively, these results provide strong evidence that Puma, like Bim, Noxa and Bid, is able to act as a direct activator.
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Patterns of stigma toward schizophrenia among the general population: A latent profile analysis.
Int J Soc Psychiatry
PUBLISHED: 10-21-2013
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Our purpose was to assess stigma toward schizophrenia in a representative sample of the Brazilian general population.
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Common pharmacophore of structurally distinct small-molecule inhibitors of intracellular retrograde trafficking of ribosome inactivating proteins.
Sci Rep
PUBLISHED: 09-09-2013
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We reported previously (±)-2-(5-methylthiophen-2-yl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one [(±)-Retro-2(cycl)] as the chemical structure of Retro-2 that showed mouse protection against ricin, a notorious ribosome inactivating protein (RIP). Herein we report our chemical resolution of (±)-Retro-2(cycl), analog synthesis, and cell-based evaluation showing that the two optically pure enantiomers and their achiral analog have nearly the same degree of cell protection against ricin as (±)-Retro-2(cycl). We also report our computational studies explaining the lack of stereo preference and revealing a common pharmacophore of structurally distinct inhibitors of intracellular retrograde trafficking of RIPs. This pharmacophore comprises a central aromatic ring o-substituted by an aromatic ring and a moiety bearing an O or S atom attached to sp(2) C atom(s). These results offer new insights into lead identification and optimization for RIP antidote development to minimize the global health threat caused by ribosome-inactivating proteins.
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Does income inequality get under the skin? A multilevel analysis of depression, anxiety and mental disorders in Sao Paulo, Brazil.
J Epidemiol Community Health
PUBLISHED: 08-01-2013
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Test the original income inequality theory, by analysing its association with depression, anxiety and any mental disorders.
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Prediction of chemotherapeutic response in unresectable non-small-cell lung cancer (NSCLC) patients by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium (MTS) assay.
Asian Pac. J. Cancer Prev.
PUBLISHED: 06-28-2013
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Selecting chemotherapy regimens guided by chemosensitivity tests can provide individualized therapies for cancer patients. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolium, inner salt (MTS) assay is one in vitro assay which has become widely used to evaluate the sensitivity to anticancer agents. The aim of this study was to evaluate the clinical applicability and accuracy of MTS assay for predicting chemotherapeutic response in unresectable NSCLC patients.
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Epidemiology of alcohol and drug use in the elderly.
Curr Opin Psychiatry
PUBLISHED: 05-22-2013
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Alcohol and drug abuse among older adults is a topic of growing public health concern. The authors review the recent epidemiological surveys of this emerging trend and outline some public health challenges for the coming future.
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Six-month open-label follow-up of risperidone long-acting injection use in pediatric bipolar disorder.
Prim Care Companion CNS Disord
PUBLISHED: 05-02-2013
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Background: Recent studies suggest that risperidone long-acting injection (RLAI) may be considered for controlling mood episodes in bipolar disorder patients who have relapsed due to medication nonadherence or failure to respond to standard therapies. Currently, no study has reported the usefulness of RLAI in youths with bipolar disorder. The aim of this study was to evaluate short-term effects of RLAI in the naturalistic treatment of early-onset bipolar disorder and its role in symptomatic remission and adherence to treatment. Method: Nineteen early-onset bipolar disorder outpatients receiving RLAI were observed in a 6-month naturalistic study at the outpatient clinic of the Child and Adolescent Affective Disorders Program at the Institute of Psychiatry of the University of São Paulo, São Paulo, Brazil. All patients met DSM-IV criteria for bipolar disorder. Clinical response to RLAI was evaluated using the Childrens Global Assessment Scale (CGAS) and Clinical Global Impressions scale (CGI) across 3 time periods: index time (T0), 8 weeks after (T1), and 24 weeks after (T2). These subjects were recruited from May 2008 to December 2009. Results: Patients receiving RLAI presented considerable improvement in global functioning (CGAS: T0 = 20.6; T1 = 42.9; and T2 = 49.2) and clinical severity (CGI: T0 = 5.9; T1 = 3.9; and T2 = 3.4). Global CGI mean scores of clinical improvement were 2.2 at T1 and 2.4 at T2. There were no significant changes in laboratory measurements and weight throughout follow-up. Conclusions: RLAI was shown to be an alternative treatment for youths with bipolar disorder failing to respond to prior medication trials or with adherence problems. Further blind, randomized controlled studies are necessary to confirm these initial findings. Trial registration: Sistema Nacional de Informaç?es Sobre Ética em Pesquisa Envolvendo Seres Humanos-Commisão Nacional de Ética em Pesquisa identifier: CAAE 0709.0.015.000-06.
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Transplantation of neural stem cells overexpressing glial cell line-derived neurotrophic factor enhances Akt and Erk1/2 signaling and neurogenesis in rats after stroke.
Chin. Med. J.
PUBLISHED: 04-06-2013
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Our previous studies have indicated that the beneficial effects of grafting neural stem cells (NSCs) overexpressing glial cell line-derived neurotrophic factor (GDNF) in rats after stroke. However, the underlying mechanisms are highly debatable. In this study, we investigated whether neurogenesis, Akt, and extracellular signal-regulated kinase 1/2 (Erk1/2) signaling were involved in this process.
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Stigma toward schizophrenia: do all psychiatrists behave the same? Latent profile analysis of a national sample of psychiatrists in Brazil.
BMC Psychiatry
PUBLISHED: 03-14-2013
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An important issue concerning the worldwide fight against stigma is the evaluation of psychiatrists beliefs and attitudes toward schizophrenia and mental illness in general. However, there is as yet no consensus on this matter in the literature, and results vary according to the stigma dimension assessed and to the cultural background of the sample. The aim of this investigation was to search for profiles of stigmatizing beliefs related to schizophrenia in a national sample of psychiatrists in Brazil.
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Substantial neuroprotection against K(+) deprivation-induced apoptosis in primary cerebellar granule neurons by novel dimer bis(propyl)-cognitin via the activation of VEGFR-2 signaling pathway.
CNS Neurosci Ther
PUBLISHED: 03-07-2013
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Neuronal loss via apoptosis in CNS is the fundamental mechanism underlying various neurodegenerative diseases. Compounds with antiapoptotic property might have therapeutic effects for these diseases. In this study, bis(propyl)-cognitin (B3C), a novel dimer that possesses anti-AChE and anti-N-methyl-d-aspartate receptor activities, was investigated for its neuroprotective effect on K(+) deprivation-induced apoptosis in cerebellar granule neurons (CGNs).
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Days out-of-role due to common physical and mental health problems: Results from the São Paulo Megacity Mental Health Survey, Brazil.
Clinics (Sao Paulo)
PUBLISHED: 02-05-2013
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To investigate the relative importance of common physical and mental disorders with regard to the number of days out-of-role (DOR; number of days for which a person is completely unable to work or carry out normal activities because of health problems) in a population-based sample of adults in the São Paulo Metropolitan Area, Brazil.
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Assessment of depression in medical patients: a systematic review of the utility of the Beck Depression Inventory-II.
Clinics (Sao Paulo)
PUBLISHED: 01-23-2013
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To perform a systematic review of the utility of the Beck Depression Inventory for detecting depression in medical settings, this article focuses on the revised version of the scale (Beck Depression Inventory-II), which was reformulated according to the DSM-IV criteria for major depression. We examined relevant investigations with the Beck Depression Inventory-II for measuring depression in medical settings to provide guidelines for practicing clinicians. Considering the inclusion and exclusion criteria seventy articles were retained. Validation studies of the Beck Depression Inventory-II, in both primary care and hospital settings, were found for clinics of cardiology, neurology, obstetrics, brain injury, nephrology, chronic pain, chronic fatigue, oncology, and infectious disease. The Beck Depression Inventory-II showed high reliability and good correlation with measures of depression and anxiety. Its threshold for detecting depression varied according to the type of patients, suggesting the need for adjusted cut-off points. The somatic and cognitive-affective dimension described the latent structure of the instrument. The Beck Depression Inventory-II can be easily adapted in most clinical conditions for detecting major depression and recommending an appropriate intervention. Although this scale represents a sound path for detecting depression in patients with medical conditions, the clinician should seek evidence for how to interpret the score before using the Beck Depression Inventory-II to make clinical decisions.
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Novel selective and irreversible mosquito acetylcholinesterase inhibitors for controlling malaria and other mosquito-borne diseases.
Sci Rep
PUBLISHED: 01-15-2013
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We reported previously that insect acetylcholinesterases (AChEs) could be selectively and irreversibly inhibited by methanethiosulfonates presumably through conjugation to an insect-specific cysteine in these enzymes. However, no direct proof for the conjugation has been published to date, and doubts remain about whether such cysteine-targeting inhibitors have desirable kinetic properties for insecticide use. Here we report mass spectrometric proof of the conjugation and new chemicals that irreversibly inhibited African malaria mosquito AChE with bimolecular inhibition rate constants (k(inact)/K(I)) of 3,604-458,597 M(-1)sec(-1) but spared human AChE. In comparison, the insecticide paraoxon irreversibly inhibited mosquito and human AChEs with k(inact)/K(I) values of 1,915 and 1,507 M(-1)sec(-1), respectively, under the same assay conditions. These results further support our hypothesis that the insect-specific AChE cysteine is a unique and unexplored target to develop new insecticides with reduced insecticide resistance and low toxicity to mammals, fish, and birds for the control of mosquito-borne diseases.
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Transient binding of an activator BH3 domain to the Bak BH3-binding groove initiates Bak oligomerization.
J. Cell Biol.
PUBLISHED: 07-04-2011
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The mechanism by which the proapoptotic Bcl-2 family members Bax and Bak release cytochrome c from mitochondria is incompletely understood. In this paper, we show that activator BH3-only proteins bind tightly but transiently to the Bak hydrophobic BH3-binding groove to induce Bak oligomerization, liposome permeabilization, mitochondrial cytochrome c release, and cell death. Analysis by surface plasmon resonance indicated that the initial binding of BH3-only proteins to Bak occurred with similar kinetics with or without detergent or mitochondrial lipids, but these reagents increase the strength of the Bak-BH3-only protein interaction. Point mutations in Bak and reciprocal mutations in the BH3-only proteins not only confirmed the identity of the interacting residues at the Bak-BH3-only protein interface but also demonstrated specificity of complex formation in vitro and in a cellular context. These observations indicate that transient protein-protein interactions involving the Bak BH3-binding groove initiate Bak oligomerization and activation.
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Psychiatry: life events and social support in late life depression.
Clinics (Sao Paulo)
PUBLISHED: 04-13-2011
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To examine the association of life events and social support in the broadly defined category of depression in late life.
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The psychosis continuum in the general population: findings from the São Paulo Epidemiologic Catchment Area Study.
Eur Arch Psychiatry Clin Neurosci
PUBLISHED: 02-23-2011
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The aim of the study was to examine the psychosis continuum in a Latin-American community setting. Data were from the Brazilian São Paulo Epidemiologic Catchment Area Study, a cross-sectional survey conducted in two boroughs of the city of São Paulo. The Composite International Diagnosis Interview (version 1.1) was applied to a probabilistic sample of 1,464 adults, who were interviewed in their household, in order to identify the presence of psychotic symptoms. A subsample was assessed with Schedules for Clinical Assessment in Neuropsychiatry interview. We described the occurrence of psychotic symptoms, categorized into subgroups according to their clinical impact, disability, and help-seeking behavior. The correlation of socio-demographic variables, depressive symptoms, and alcohol and substance use disorders with those psychotic subgroups was analyzed. Polychotomic logistic regression tested the associations between subgroups of psychosis (clinical and subclinical) and the correlates. Of the total sample, 38.0% presented at least one lifetime psychotic symptom, 1.9% met the criteria for an ICD-10 diagnosis of non-affective psychosis, 5.4% presented clinically relevant psychotic symptoms, and 30.7% endorsed clinically non-relevant symptoms. The most common psychotic symptom was delusion with a plausible explanation (in 18.6%). The presence of any psychiatric diagnosis was associated with the presence of psychotic symptoms (OR range, 1.9-8.9). Subclinical psychosis subgroups were found to be associated with the 18-24 year age bracket, chronic depressive mood, and alcohol use disorder. Our results support the concept of a psychosis continuum in Latin-American populations, suggesting that different risk factors influence their manifestation across the continuum.
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Small-molecule inhibitor leads of ribosome-inactivating proteins developed using the doorstop approach.
PLoS ONE
PUBLISHED: 02-16-2011
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Ribosome-inactivating proteins (RIPs) are toxic because they bind to 28S rRNA and depurinate a specific adenine residue from the ?-sarcin/ricin loop (SRL), thereby inhibiting protein synthesis. Shiga-like toxins (Stx1 and Stx2), produced by Escherichia coli, are RIPs that cause outbreaks of foodborne diseases with significant morbidity and mortality. Ricin, produced by the castor bean plant, is another RIP lethal to mammals. Currently, no US Food and Drug Administration-approved vaccines nor therapeutics exist to protect against ricin, Shiga-like toxins, or other RIPs. Development of effective small-molecule RIP inhibitors as therapeutics is challenging because strong electrostatic interactions at the RIP•SRL interface make drug-like molecules ineffective in competing with the rRNA for binding to RIPs. Herein, we report small molecules that show up to 20% cell protection against ricin or Stx2 at a drug concentration of 300 nM. These molecules were discovered using the doorstop approach, a new approach to protein•polynucleotide inhibitors that identifies small molecules as doorstops to prevent an active-site residue of an RIP (e.g., Tyr80 of ricin or Tyr77 of Stx2) from adopting an active conformation thereby blocking the function of the protein rather than contenders in the competition for binding to the RIP. This work offers promising leads for developing RIP therapeutics. The results suggest that the doorstop approach might also be applicable in the development of other protein•polynucleotide inhibitors as antiviral agents such as inhibitors of the Z-DNA binding proteins in poxviruses. This work also calls for careful chemical and biological characterization of drug leads obtained from chemical screens to avoid the identification of irrelevant chemical structures and to avoid the interference caused by direct interactions between the chemicals being screened and the luciferase reporter used in screening assays.
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Application of the Spielbergers State-Trait Anger Expression Inventory in clinical patients.
Arq Neuropsiquiatr
PUBLISHED: 05-14-2010
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To examine the factor structure of the Portuguese version of State-Trait Anger Expression Inventory (STAXI) in clinical patients.
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The influence of the comorbidity between depression and alcohol use disorder on suicidal behaviors in the São Paulo Epidemiologic Catchment Area Study, Brazil.
Rev Bras Psiquiatr
PUBLISHED: 04-27-2010
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To investigate in a community sample the association of suicide-related cognitions and behaviors ("thoughts of death", "desire for death", "suicidal thoughts", and "suicidal attempts") with the comorbidity of depressive disorders (major depressive episode or dysthymia) and alcohol or substance use disorders.
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Kinetic analysis of interactions between alkylene-linked bis-pyridiniumaldoximes and human acetylcholinesterases inhibited by various organophosphorus compounds.
Biochem. Pharmacol.
PUBLISHED: 04-15-2010
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The therapeutic approach of organophosphorus compound (OP) intoxications is to reactivate the inhibited enzyme acetylcholinesterase (AChE). Numerous studies demonstrated a limited efficacy of standard oxime-based reactivators against different nerve agents such as tabun and cyclosarin. This emphasizes research for more effective oximes. In the present study, reactivation kinetics of tabun-, sarin-, cyclosarin-, VX- or paraoxon-ethyl-inhibited human AChE (hAChE) with a homologous series of bis-ortho-pyridiniumaldoximes, Ortho-4 - Ortho-9, was investigated with a robot-assisted setting, allowing determination of second-order reactivation rate constants as well as model calculations. The reactivation constants of Ortho-4 - Ortho-9 resulted in marked differences of affinity and reactivity depending on the OP structure and the linker length of the oximes. In general, the K(D) values decreased with increasing linker length. Reactivity increased from Ortho-4 to Ortho-6 for PXE- and VX-inhibited hAChE and from Ortho-4 to Ortho-7 for GA-inhibited hAChE and decreased again with Ortho-8 and Ortho-9. In contrast, k(r) decreased with increasing linker length for sarin- and cyclosarin-inhibited hAChE. In view of the pronounced decrease of K(D) from Ortho-4 to Ortho-9, the k(r2) values increased with all tested OP. Hence, the ratios of K(I)/K(D) and of K(I)/k(r2) showed that in almost all cases the affinity of Ortho-N to the native hAChE was higher than to OP-inhibited enzyme. Model calculations indicated that Ortho-6 - Ortho-9 could be superior to obidoxime in reactivating tabun-inhibited hAChE. Finally, these data emphasize the need to develop oximes with a higher selective affinity towards OP-inhibited hAChE in order to minimize possible side effects.
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Small molecules showing significant protection of mice against botulinum neurotoxin serotype A.
PLoS ONE
PUBLISHED: 03-11-2010
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Botulinum neurotoxin serotype A (BoNTA) causes a life-threatening neuroparalytic disease known as botulism that could afflict large, unprotected populations if the toxin were employed in an act of bioterrorism. Current post-exposure therapy is limited to symptomatic treatment or passive immunization that is effective for treating infant botulism at a cost of US $45,300 per treatment regimen. Antibodies can neutralize the extracellular but not the intracellular BoNTA. Moreover, antibody production, storage, and administration in a mass casualty scenario pose logistical challenges. Alternatively, small-molecule inhibitors of BoNTA endopeptidase (BoNTAe) are sought to antagonize the extracellular or intracellular toxin. While several such molecules reportedly demonstrated efficacy in protecting cells against BoNTA, there is scant information to show that small molecules can significantly protect mammals against BoNTA. Herein we report the development of effective small-molecules BoNTAe inhibitors with promising in vivo pharmacokinetics. One such molecule has an in vivo half-life of 6.5 hours and is devoid of obvious sign of toxicity. Pre-treatment with this molecule at 2 mg/kg protected 100% and 70% of treated mice against BoNTA at 5 times of its median-lethal dose during the periods of 2 and 4 half-lives of the inhibitor, respectively. In contrast, 40% and 0% of untreated mice survived during the respective periods. Similar levels of protection were also observed with two other small molecules. These results demonstrate that small molecules can significantly protect mice against BoNTA and support the pursuit of small-molecule antagonists as a cost-effective alternative or as an adjunct to passive immunity for treating botulism.
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Current development and patents on high-brightness white LED for illumination.
Recent Pat Nanotechnol
PUBLISHED: 03-11-2010
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In this paper, we reviewed the current development and patents for the application of high-brightness and high-efficiency white light-emitting diode (LED). The high-efficiency GaN nanostructures, such as disk, pyramid, and rod were grown on LiAlO(2) substrate by plasma-assisted molecular-beam epitaxy, and a model was developed to demonstrate the growth of the GaN nanostructures. Based on the results, the GaN disk p-n junction was designed for the application of high brightness and high efficiency white LED.
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Series of 2D and 3D coordination polymers based on 1,2,3,4-benzenetetracarboxylate and N-donor ligands: synthesis, topological structures, and photoluminescent properties.
Inorg Chem
PUBLISHED: 01-26-2010
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Nine new coordination polymers, namely, [Mn(2)(L)(H(2)O)(4)].H(2)O (1), [Cd(L)(0.5)(H(2)O)] (2), [Zn(5)(L)(2)(mu(3)-O)(2)(H(2)O)(4)].2H(2)O (3), [Zn(4)(L)(2)(mu(3)-O)(2)][Zn(H(2)O)(5)].2H(2)O (4), [Zn(2)(L)(biim-4)(0.5)(H(2)O)(3)].H(2)O (5), [Cd(2)(L)(bpy)(H(2)O)].2H(2)O.0.5(CH(3)CH(2)OH) (6), [Cu(2)(H(2)L)(2)(bpy)(2)] (7), [Cu(2)(L)(bpy)(H(2)O)] (8), and [Cu(2)(L)(bpy)(1.5)(H(2)O)(2.5)] (9), where H(4)L = 1,2,3,4-benzenetetracarboxylic acid, biim-4 = 1,1-(1,4-butanediyl)bis(imidazole), and bpy = 4,4-bipyridine, have been synthesized under hydrothermal conditions. Compound 1 displays a rare trinodal (3,4,7)-connected (4(2).6)(4(5).6)(4(7).6(8).8(6)) topology. 2 possesses an alpha-Po net. 3 is a novel 3D framework based on pentanuclear Zn(II) clusters. By adjustment of the pH values of the reaction mixture of 3 with a Na(2)CO(3) solution, a structurally different compound, 4, was obtained, which exhibits a 3D porous framework with the [Zn(H(2)O)(6)](2+) cations located in the channels. 5 is an unusual example of a trinodal (3,5)-connected network with a Schlafli symbol of (4(2).6)(6(2).8)(4(2).6(2).8(5).10), whereas 6, containing tetranuclear Cd(II) clusters, shows a rare (4,6)-connected (4(4).6(2))(2)(4(4).6(10).8) topology. 7 exhibits a unique polythreading network, while 8 displays a scarce trinodal (3,4,5)-connected self-penetrating network. In comparison with 8, the chiral compound 9 possesses an unprecedented tetranodal (2,4)-connected (7)(7(5).11)(6(2).7(3).8)(2)(6.7(4).10)(2) topology. The effects of the carboxylate ligands, the pH values, the reaction temperatures, the central metals, and the neutral ligands were elucidated. The IR spectra, thermogravimetric analysis, and luminescent properties for the compounds were also investigated.
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Insect-specific irreversible inhibitors of acetylcholinesterase in pests including the bed bug, the eastern yellowjacket, German and American cockroaches, and the confused flour beetle.
Chem. Biol. Interact.
PUBLISHED: 01-12-2010
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Insecticides directed against acetylcholinesterase (AChE) are facing increased resistance among target species as well as increasing concerns for human toxicity. The result has been a resurgence of disease vectors, insects destructive to agriculture, and residential pests. We previously reported a free cysteine (Cys) residue at the entrance to the AChE active site in some insects but not higher vertebrates. We also reported Cys-targeting methanethiosulfonate molecules (AMTSn), which, under conditions that spared human AChE, caused total irreversible inhibition of aphid AChE, 95% inhibition of AChE from the malaria vector mosquito (Anopheles gambia), and >80% inhibition of activity from the yellow fever mosquito (Aedes aegypti) and northern house mosquito (Culex pipiens). We now find the same compounds inhibit AChE from cockroaches (Blattella germanica and Periplaneta americana), the flour beetle (Tribolium confusum), the multi-colored Asian ladybird beetle (Harmonia axyridis), the bed bug (Cimex lectularius), and a wasp (Vespula maculifrons), with IC(50) values of approximately 1-11muM. Our results support further study of Cys-targeting inhibitors as conceptually novel insecticides that may be free of resistance in a range of insect pests and disease vectors and, compared with current compounds, should demonstrate much lower toxicity to mammals, birds, and fish.
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Potent new small-molecule inhibitor of botulinum neurotoxin serotype A endopeptidase developed by synthesis-based computer-aided molecular design.
PLoS ONE
PUBLISHED: 09-02-2009
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Botulinum neurotoxin serotype A (BoNTA) causes a life-threatening neuroparalytic disease known as botulism. Current treatment for post exposure of BoNTA uses antibodies that are effective in neutralizing the extracellular toxin to prevent further intoxication but generally cannot rescue already intoxicated neurons. Effective small-molecule inhibitors of BoNTA endopeptidase (BoNTAe) are desirable because such inhibitors potentially can neutralize the intracellular BoNTA and offer complementary treatment for botulism. Previously we reported a serotype-selective, small-molecule BoNTAe inhibitor with a K(i) (app) value of 3.8+/-0.8 microM. This inhibitor was developed by lead identification using virtual screening followed by computer-aided optimization of a lead with an IC(50) value of 100 microM. However, it was difficult to further improve the lead from micromolar to even high nanomolar potency due to the unusually large enzyme-substrate interface of BoNTAe. The enzyme-substrate interface area of 4,840 A(2) for BoNTAe is about four times larger than the typical protein-protein interface area of 750-1,500 A(2). Inhibitors must carry several functional groups to block the unusually large interface of BoNTAe, and syntheses of such inhibitors are therefore time-consuming and expensive. Herein we report the development of a serotype-selective, small-molecule, and competitive inhibitor of BoNTAe with a K(i) value of 760+/-170 nM using synthesis-based computer-aided molecular design (SBCAMD). This new approach accounts the practicality and efficiency of inhibitor synthesis in addition to binding affinity and selectivity. We also report a three-dimensional model of BoNTAe in complex with the new inhibitor and the dynamics of the complex predicted by multiple molecular dynamics simulations, and discuss further structural optimization to achieve better in vivo efficacy in neutralizing BoNTA than those of our early micromolar leads. This work provides new insight into structural modification of known small-molecule BoNTAe inhibitors. It also demonstrates that SBCAMD is capable of improving potency of an inhibitor lead by nearly one order of magnitude, even for BoNTAe as one of the most challenging protein targets. The results are insightful for developing effective small-molecule inhibitors of protein targets with large active sites.
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Crystal structures of oxime-bound fenamiphos-acetylcholinesterases: reactivation involving flipping of the His447 ring to form a reactive Glu334-His447-oxime triad.
Biochem. Pharmacol.
PUBLISHED: 07-01-2009
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Organophosphorus insecticides and nerve agents inhibit the vital enzyme acetylcholinesterase by covalently bonding to the catalytic serine residue of the enzyme. Oxime-based reactivators, such as [(E)-[1-[(4-carbamoylpyridin-1-ium-1-yl)methoxymethyl]pyridin-2-ylidene]methyl]-oxoazanium dichloride (HI-6) and 1,7-heptylene-bis-N,N-2-pyridiniumaldoxime dichloride (Ortho-7), restore the organophosphate-inhibited enzymatic activity by cleaving the phosphorous conjugate. In this article, we report the intermolecular interactions between Mus musculus acetylcholinesterase inhibited by the insecticide fenamiphos (fep-mAChE) and HI-6 or Ortho-7 revealed by a combination of crystallography and kinetics. The crystal structures of the two oxime-bound fep-mAChE complexes show that both oximes interact with the peripheral anionic site involving different conformations of Trp286 and different peripheral-site residues (Tyr124 for HI-6 and Tyr72 for Ortho-7). Moreover, residues at catalytic site of the HI-6-bound fep-mAChE complex adopt conformations that are similar to those in the apo mAChE, whereas significant conformational changes are observed for the corresponding residues in the Ortho-7-bound fep-mAChE complex. Interestingly, flipping of the His447 imidazole ring allows the formation of a hydrogen bonding network among the Glu334-His447-Ortho-7 triad, which presumably deprotonates the Ortho-7 oxime hydroxyl group, increases the nucleophilicity of the oxime group, and leads to cleavage of the phosphorous conjugate. These results offer insights into a detailed reactivation mechanism for the oximes and development of improved reactivators.
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Selective and irreversible inhibitors of mosquito acetylcholinesterases for controlling malaria and other mosquito-borne diseases.
PLoS ONE
PUBLISHED: 06-20-2009
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New insecticides are urgently needed because resistance to current insecticides allows resurgence of disease-transmitting mosquitoes while concerns for human toxicity from current compounds are growing. We previously reported the finding of a free cysteine (Cys) residue at the entrance of the active site of acetylcholinesterase (AChE) in some insects but not in mammals, birds, and fish. These insects have two AChE genes (AP and AO), and only AP-AChE carries the Cys residue. Most of these insects are disease vectors such as the African malaria mosquito (Anopheles gambiae sensu stricto) or crop pests such as aphids. Recently we reported a Cys-targeting small molecule that irreversibly inhibited all AChE activity extracted from aphids while an identical exposure caused no effect on the human AChE. Full inhibition of AChE in aphids indicates that AP-AChE contributes most of the enzymatic activity and suggests that the Cys residue might serve as a target for developing better aphicides. It is therefore worth investigating whether the Cys-targeting strategy is applicable to mosquitocides. Herein, we report that, under conditions that spare the human AChE, a methanethiosulfonate-containing molecule at 6 microM irreversibly inhibited 95% of the AChE activity extracted from An. gambiae s. str. and >80% of the activity from the yellow fever mosquito (Aedes aegypti L.) or the northern house mosquito (Culex pipiens L.) that is a vector of St. Louis encephalitis. This type of inhibition is fast ( approximately 30 min) and due to conjugation of the inhibitor to the active-site Cys of mosquito AP-AChE, according to our observed reactivation of the methanethiosulfonate-inhibited AChE by 2-mercaptoethanol. We also note that our sulfhydryl agents partially and irreversibly inhibited the human AChE after prolonged exposure (>4 hr). This slow inhibition is due to partial enzyme denaturation by the inhibitor and/or micelles of the inhibitor, according to our studies using atomic force microscopy, circular dichroism spectroscopy, X-ray crystallography, time-resolved fluorescence spectroscopy, and liquid chromatography triple quadrupole mass spectrometry. These results support our view that the mosquito-specific Cys is a viable target for developing new mosquitocides to control disease vectors and to alleviate resistance problems with reduced toxicity toward non-target species.
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Mechanism of bis(7)-tacrine inhibition of GABA-activated current in cultured rat hippocampal neurons.
Neuropharmacology
PUBLISHED: 03-11-2009
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Bis(7)-tacrine is a novel dimeric acetylcholinesterase inhibitor derived from tacrine that shows promise for the treatment of Alzheimers disease. We have previously reported that bis(7)-tacrine inhibits GABA(A) receptors. In the present study we investigated the mechanism of bis(7)-tacrine inhibition of GABA(A) receptor function using whole-cell patch-clamp recording in cultured rat hippocampal neurons. Bis(7)-tacrine produced a gradual decline of GABA-activated current to a steady-state, but this was not an indication of use-dependence, as the gradually declining component could be eliminated by exposure to bis(7)-tacrine prior to GABA application. In addition, bis(7)-tacrine inhibition did not require the presence of agonist, and GABA-activated current recovered completely from inhibition by bis(7)-tacrine in the absence of agonist. The slow onset of inhibition by bis(7)-tacrine was not apparently due to an action at an intracellular site, as inclusion of 25 microM bis(7)-tacrine in the recording pipette did not alter inhibition by bis(7)-tacrine applied externally. Bis(7)-tacrine shifted the GABA concentration-response curve to the right in a parallel manner and the pA(2) value estimated from a Schild plot was 5.7. Bis(7)-tacrine increased the time constant of activation of GABA-gated ion channels without affecting the time constants of deactivation or desensitization. These results suggest that bis(7)-tacrine is a competitive GABA(A) receptor antagonist with slow onset and offset kinetics. The competitive inhibition of GABA receptors by bis(7)-tacrine could contribute to its ability to enhance memory.
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Structure of HI-6*sarin-acetylcholinesterase determined by X-ray crystallography and molecular dynamics simulation: reactivator mechanism and design.
PLoS ONE
PUBLISHED: 02-25-2009
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Organophosphonates such as isopropyl metylphosphonofluoridate (sarin) are extremely toxic as they phosphonylate the catalytic serine residue of acetylcholinesterase (AChE), an enzyme essential to humans and other species. Design of effective AChE reactivators as antidotes to various organophosphonates requires information on how the reactivators interact with the phosphonylated AChEs. However, such information has not been available hitherto because of three main challenges. First, reactivators are generally flexible in order to change from the ground state to the transition state for reactivation; this flexibility discourages determination of crystal structures of AChE in complex with effective reactivators that are intrinsically disordered. Second, reactivation occurs upon binding of a reactivator to the phosphonylated AChE. Third, the phosphorous conjugate can develop resistance to reactivation. We have identified crystallographic conditions that led to the determination of a crystal structure of the sarin(nonaged)-conjugated mouse AChE in complex with [(E)-[1-[(4-carbamoylpyridin-1-ium-1-yl)methoxymethyl]pyridin-2-ylidene]methyl]-oxoazanium dichloride (HI-6) at a resolution of 2.2 A. In this structure, the carboxyamino-pyridinium ring of HI-6 is sandwiched by Tyr124 and Trp286, however, the oxime-pyridinium ring is disordered. By combining crystallography with microsecond molecular dynamics simulation, we determined the oxime-pyridinium ring structure, which shows that the oxime group of HI-6 can form a hydrogen-bond network to the sarin isopropyl ether oxygen, and a water molecule is able to form a hydrogen bond to the catalytic histidine residue and subsequently deprotonates the oxime for reactivation. These results offer insights into the reactivation mechanism of HI-6 and design of better reactivators.
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A selective small-molecule inhibitor of c-Jun N-terminal kinase 1.
FEBS Lett.
PUBLISHED: 02-24-2009
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Indiscriminately suppressing total c-Jun N-terminal kinase (JNK) activity is not an appropriate strategy because each JNK appears to have a distinct function in cancer, asthma, diabetes, or Parkinsons disease. Herein, we report that 7-(6-N-phenylaminohexyl)amino-2H-anthra[1,9-cd]pyrazol-6-one (AV-7) inhibited JNK1 activity, but not JNK2 or JNK3. We found that ultraviolet B (UVB) induced c-Jun phosphorylation and sub-G1 accumulation in JNK2(-/-) murine embryonic fibroblasts, which contain an abundance of JNK1, but not JNK2. These results demonstrate that AV-7 is an isoform selective small-molecule inhibitor of JNK1 activity, which might be developed as a therapeutic against diabetes.
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Selective and irreversible inhibitors of aphid acetylcholinesterases: steps toward human-safe insecticides.
PLoS ONE
PUBLISHED: 02-04-2009
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Aphids, among the most destructive insects to world agriculture, are mainly controlled by organophosphate insecticides that disable the catalytic serine residue of acetylcholinesterase (AChE). Because these agents also affect vertebrate AChEs, they are toxic to non-target species including humans and birds. We previously reported that a cysteine residue (Cys), found at the AChE active site in aphids and other insects but not mammals, might serve as a target for insect-selective pesticides. However, aphids have two different AChEs (termed AP and AO), and only AP-AChE carries the unique Cys. The absence of the active-site Cys in AO-AChE might raise concerns about the utility of targeting that residue. Herein we report the development of a methanethiosulfonate-containing small molecule that, at 6.0 microM, irreversibly inhibits 99% of all AChE activity extracted from the greenbug aphid (Schizaphis graminum) without any measurable inhibition of the human AChE. Reactivation studies using beta-mercaptoethanol confirm that the irreversible inhibition resulted from the conjugation of the inhibitor to the unique Cys. These results suggest that AO-AChE does not contribute significantly to the overall AChE activity in aphids, thus offering new insight into the relative functional importance of the two insect AChEs. More importantly, by demonstrating that the Cys-targeting inhibitor can abolish AChE activity in aphids, we can conclude that the unique Cys may be a viable target for species-selective agents to control aphids without causing human toxicity and resistance problems.
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Configurational entropy in protein-peptide binding: computational study of Tsg101 ubiquitin E2 variant domain with an HIV-derived PTAP nonapeptide.
J. Mol. Biol.
PUBLISHED: 01-30-2009
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Configurational entropy is thought to influence biomolecular processes, but there are still many open questions about this quantity, including its magnitude, its relationship to molecular structure, and the importance of correlation. The mutual information expansion (MIE) provides a novel and systematic approach to extracting configurational entropy changes due to correlated motions from molecular simulations. We present the first application of the MIE method to protein-ligand binding using multiple molecular dynamics simulations to study the association of the ubiquitin E2 variant domain of the protein Tsg101 and an HIV-derived nonapeptide. This investigation utilizes the second-order MIE approximation, which accounts for correlations between all pairs of degrees of freedom. The computed change in configurational entropy is large and has a major contribution from changes in pairwise correlation. The results also reveal intricate structure-entropy relationships. Thus, the present analysis suggests that in order for a model of binding to be accurate, it must include a careful accounting of configurational entropy changes.
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Structure-based discovery of dengue virus protease inhibitors.
Antiviral Res.
PUBLISHED: 01-05-2009
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Dengue virus belongs to the family Flaviviridae and is a major emerging pathogen for which the development of vaccines and antiviral therapy has seen little success. The NS3 viral protease is a potential target for antiviral drugs since it is required for virus replication. The goal of this study was to identify novel dengue virus (type 2; DEN2V) protease inhibitors for eventual development as effective anti-flaviviral drugs. The EUDOC docking program was used to computationally screen a small-molecule library for compounds that dock into the P1 pocket and the catalytic site of the DEN2V NS3 protease domain apo-structure [Murthy, K., Clum, S., Padmanabhan, R., 1999. Crystal structure and insights into interaction of the active site with substrates by molecular modeling and structural analysis of mutational effects. J. Biol. Chem. 274, 5573-5580] and the Bowman-Birk inhibitor-bound structure [Murthy, K., Judge, K., DeLucas, L., Padmanabhan, R., 2000. Crystal structure of dengue virus NS3 protease in complex with a Bowman-Birk inhibitor: implications for flaviviral polyprotein processing and drug design. J. Mol. Biol. 301, 759-767]. The top 20 computer-identified hits that demonstrated the most favorable scoring "energies" were selected for in vitro assessment of protease inhibition. Preliminary protease activity assays demonstrated that more than half of the tested compounds were soluble and exhibited in vitro inhibition of the DEN2V protease. Two of these compounds also inhibited viral replication in cell culture experiments, and thus are promising compounds for further development.
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Validation of the Brazilian Portuguese version of the Beck Depression Inventory-II in a community sample.
Rev Bras Psiquiatr
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The Beck Depression Inventory (BDI) is used worldwide for detecting depressive symptoms. This questionnaire has been revised (1996) to match the DSM-IV criteria for a major depressive episode. We assessed the reliability and the validity of the Brazilian Portuguese version of the BDI-II for non-clinical adults.
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The more information, the more negative stigma towards schizophrenia: Brazilian general population and psychiatrists compared.
Psychiatry Res
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Findings on stigmatizing attitudes toward individuals with schizophrenia have been inconsistent in comparisons between mental health professionals and members of the general public. In this regard, it is important to obtain data from understudied sociocultural settings, and to examine how attitudes toward mental illness vary in such settings. Nationwide samples of 1015 general population individuals and 1414 psychiatrists from Brazil were recruited between 2009 and 2010. Respondents from the general population were asked to identify an unlabeled schizophrenia case vignette. Psychiatrists were instructed to consider "someone with stabilized schizophrenia". Stereotypes, perceived prejudice and social distance were assessed. For the general population, stigma determinants replicated findings from the literature. The level of the vignettes identification constituted an important correlate. For psychiatrists, determinants correlated in the opposite direction. When both samples were compared, psychiatrists showed the highest scores in stereotypes and perceived prejudice; for the general population, the better they recognized the vignette, the higher they scored in those dimensions. Psychiatrists reported the lowest social distance scores compared with members of the general population. Knowledge about schizophrenia thus constituted an important determinant of stigma; consequently, factors influencing stigma should be further investigated in the general population and in psychiatrists as well.
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Regulation of error-prone translesion synthesis by Spartan/C1orf124.
Nucleic Acids Res.
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Translesion synthesis (TLS) employs low fidelity polymerases to replicate past damaged DNA in a potentially error-prone process. Regulatory mechanisms that prevent TLS-associated mutagenesis are unknown; however, our recent studies suggest that the PCNA-binding protein Spartan plays a role in suppression of damage-induced mutagenesis. Here, we show that Spartan negatively regulates error-prone TLS that is dependent on POLD3, the accessory subunit of the replicative DNA polymerase Pol ?. We demonstrate that the putative zinc metalloprotease domain SprT in Spartan directly interacts with POLD3 and contributes to suppression of damage-induced mutagenesis. Depletion of Spartan induces complex formation of POLD3 with Rev1 and the error-prone TLS polymerase Pol ?, and elevates mutagenesis that relies on POLD3, Rev1 and Pol ?. These results suggest that Spartan negatively regulates POLD3 function in Rev1/Pol ?-dependent TLS, revealing a previously unrecognized regulatory step in error-prone TLS.
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Chemical structure of Retro-2, a compound that protects cells against ribosome-inactivating proteins.
Sci Rep
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Shiga-like toxins and ricin are ribosome-inactivating proteins (RIPs) that are lethal to mammals and pose a global health threat. No clinical vaccines or therapeutics currently exist to protect against these RIPs. Two small molecules (Retro-1 and Retro-2) were discovered with high-throughput screening and reported for their protection of cells against RIPs. Of great significance, Retro-2, reported as (E)-2-(((5-methylthiophen-2-yl)methylene)amino)-N-phenylbenzamide, fully protected mice from lethal nasal challenge with ricin. Herein, we report studies showing that the chemical structure of Retro-2 is (±)-2-(5-methylthiophen-2-yl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one rather than (E)-2-(((5-methylthiophen-2-yl)methylene)amino)-N-phenylbenzamide. The latter is an achiral molecule that converts spontaneously to the former, which is a racemate and showed cell protection against RIPs. This calls for attention to (±)-2-(5-methylthiophen-2-yl)-3-phenyl-2,3-dihydroquinazolin-4(1H)-one as a promising RIP inhibitor and for chemical characterization of drug leads obtained from high-throughput screens.
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6-Chloro-N(4),N(4)-dimethyl-pyrimidine-2,4-diamine.
Acta Crystallogr Sect E Struct Rep Online
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The asymmetric unit of the title compound, C(6)H(9)ClN(4), contains four independent mol-ecules (A, B, C and D). Their main difference is the torsion angles, ranging from 1.6?(5) to 5.9?(5)°, between the methyl group and the pyrimidine plane. A pair of inter-molecular N-H?N hydrogen bonds link mol-ecules A and C into a twisted dimer with a dihedral angle of 32.9?(1)° between the two pyrimidine rings, creating an R(2) (2)(8) motif. In the packing, each two mol-ecules of B, C and D form centrosymmetric dimers through two inter-molecular N-H?N hydrogen bonds, locally creating R(2) (2)(8) motifs. The dimers of C and D are alternately bridged by A into an infinite zigzag strip, locally creating two different R(2) (2)(8) motifs with dihedral angles of 32.9?(1) and 63.4?(1)° between the pyrimidine rings. Finally, these strips together with the dimers of B associate into a complicated three-dimensional framework.
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Gender differences in drinking patterns and alcohol-related problems in a community sample in São Paulo, Brazil.
Clinics (Sao Paulo)
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To investigate drinking patterns and gender differences in alcohol-related problems in a Brazilian population, with an emphasis on the frequency of heavy drinking.
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Cholinergic and non-cholinergic functions of two acetylcholinesterase genes revealed by gene-silencing in Tribolium castaneum.
Sci Rep
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We compared biological functions of two acetylcholinesterase genes (TcAce1 and TcAce2) in Tribolium castaneum, a globally distributed major pest of stored grain products and an emerging model organism, by using RNA interference. Although both genes expressed at all developmental stages and mainly in the brain, the transcript level of TcAce1 was 1.2- to 8.7-fold higher than that of TcAce2, depending on developmental stages. Silencing TcAce1 in 20-day larvae led to 100% mortality within two weeks after eclosion and increased larval susceptibilities to anticholinesterase insecticides. In contrast, silencing TcAce2 did not show insect mortality and significantly affect insecticide susceptibility, but delayed insect development and reduced female egg-laying and egg hatching. These results demonstrate for the first time that TcAce1 plays a major role in cholinergic functions and is the target of anticholinesterase insecticides, whereas TcAce2 plays an important, non-cholinergic role in female reproduction, embryo development, and growth of offspring.
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Genome organization, phylogenies, expression patterns, and three-dimensional protein models of two acetylcholinesterase genes from the red flour beetle.
PLoS ONE
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Since the report of a paralogous acetylcholinesterase (AChE, EC3.1.1.7) gene in the greenbug (Schizaphis graminum) in 2002, two different AChE genes (Ace1 and Ace2) have been identified in each of at least 27 insect species. However, the gene models of Ace1 and Ace2, and their molecular properties have not yet been comprehensively analyzed in any insect species. In this study, we sequenced the full-length cDNAs, computationally predicted the corresponding three-dimensional protein models, and profiled developmental stage and tissue-specific expression patterns of two Ace genes from the red flour beetle (Tribolium castaneum; TcAce1 and TcAce2), a globally distributed major pest of stored grain products and an emerging model organism. TcAce1 and TcAce2 encode 648 and 604 amino acid residues, respectively, and have conserved motifs including a choline-binding site, a catalytic triad, and an acyl pocket. Phylogenetic analysis show that both TcAce genes are grouped into two insect Ace clusters and TcAce1 is completely diverged from TcAce2, suggesting that these two genes evolve from their corresponding Ace gene lineages in insect species. In addition, TcAce1 is located on chromosome 5, whereas TcAce2 is located on chromosome 2. Reverse transcription polymerase chain reaction (PCR) and quantitative real-time PCR analyses indicate that both genes are virtually transcribed in all the developmental stages and predominately expressed in the insect brain. Our computational analyses suggest that the TcAce1 protein is a robust acetylcholine (ACh) hydrolase and has susceptibility to sulfhydryl agents whereas the TcAce2 protein is not a catalytically efficient ACh hydrolase.
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Bak Conformational Changes Induced by Ligand Binding: Insight into BH3 Domain Binding and Bak Homo-Oligomerization.
Sci Rep
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Recently we reported that the BH3-only proteins Bim and Noxa bind tightly but transiently to the BH3-binding groove of Bak to initiate Bak homo-oligomerization. However, it is unclear how such tight binding can induce Bak homo-oligomerization. Here we report the ligand-induced Bak conformational changes observed in 3D models of Noxa·Bak and Bim·Bak refined by molecular dynamics simulations. In particular, upon binding to the BH3-binding groove, Bim and Noxa induce a large conformational change of the loop between helices 1 and 2 and in turn partially expose a remote groove between helices 1 and 6 in Bak. These observations, coupled with the reported experimental data, suggest formation of a pore-forming Bak octamer, in which the BH3-binding groove is at the interface on one side of each monomer and the groove between helices 1 and 6 is at the interface on the opposite side, initiated by ligand binding to the BH3-binding groove.
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Mental disorders in megacities: findings from the São Paulo megacity mental health survey, Brazil.
PLoS ONE
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World population growth is projected to be concentrated in megacities, with increases in social inequality and urbanization-associated stress. São Paulo Metropolitan Area (SPMA) provides a forewarning of the burden of mental disorders in urban settings in developing world. The aim of this study is to estimate prevalence, severity, and treatment of recently active DSM-IV mental disorders. We examined socio-demographic correlates, aspects of urban living such as internal migration, exposure to violence, and neighborhood-level social deprivation with 12-month mental disorders.
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Novel and viable acetylcholinesterase target site for developing effective and environmentally safe insecticides.
Curr Drug Targets
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Insect pests are responsible for human suffering and financial losses worldwide. New and environmentally safe insecticides are urgently needed to cope with these serious problems. Resistance to current insecticides has resulted in a resurgence of insect pests, and growing concerns about insecticide toxicity to humans discourage the use of insecticides for pest control. The small market for insecticides has hampered insecticide development; however, advances in genomics and structural genomics offer new opportunities to develop insecticides that are less dependent on the insecticide market. This review summarizes the literature data that support the hypothesis that an insect-specific cysteine residue located at the opening of the acetylcholinesterase active site is a promising target site for developing new insecticides with reduced off-target toxicity and low propensity for insect resistance. These data are used to discuss the differences between targeting the insect-specific cysteine residue and targeting the ubiquitous catalytic serine residue of acetylcholinesterase from the perspective of reducing off-target toxicity and insect resistance. Also discussed is the prospect of developing cysteine-targeting anticholinesterases as effective and environmentally safe insecticides for control of disease vectors, crop damage, and residential insect pests within the financial confines of the present insecticide market.
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